Merge remote-tracking branch 'upstream/develop' into feature/vm_gas_counter_refactor

Conflicts:
	libethereum/ExtVM.cpp
	libevm/SmartVM.h
	libevm/VM.cpp
	libevm/VM.h
	libevm/VMFace.h

1 files changed, 138 insertions, 2 deletions

diff --git a/libsolidity/SolidityOptimizer.cpp b/libsolidity/SolidityOptimizer.cpp
index 3cb6a536..744fc48a 100644
--- a/libsolidity/SolidityOptimizer.cpp
+++ b/libsolidity/SolidityOptimizer.cpp
@@ -29,6 +29,7 @@
 #include <libevmasm/CommonSubexpressionEliminator.h>
 #include <libevmasm/ControlFlowGraph.h>
 #include <libevmasm/Assembly.h>
+#include <libevmasm/BlockDeduplicator.h>
 
 using namespace std;
 using namespace dev::eth;
@@ -96,7 +97,7 @@ public:
 	{
 		eth::KnownState state;
 		for (auto const& item: addDummyLocations(_input))
-			state.feedItem(item);
+			state.feedItem(item, true);
 		return state;
 	}
 
@@ -125,7 +126,7 @@ public:
 		BOOST_CHECK_EQUAL_COLLECTIONS(_expectation.begin(), _expectation.end(), output.begin(), output.end());
 	}
 
-	void checkCFG(AssemblyItems const& _input, AssemblyItems const& _expectation)
+	AssemblyItems getCFG(AssemblyItems const& _input)
 	{
 		AssemblyItems output = _input;
 		// Running it four times should be enough for these tests.
@@ -138,6 +139,12 @@ public:
 					 back_inserter(optItems));
 			output = move(optItems);
 		}
+		return output;
+	}
+
+	void checkCFG(AssemblyItems const& _input, AssemblyItems const& _expectation)
+	{
+		AssemblyItems output = getCFG(_input);
 		BOOST_CHECK_EQUAL_COLLECTIONS(_expectation.begin(), _expectation.end(), output.begin(), output.end());
 	}
 
@@ -251,6 +258,106 @@ BOOST_AUTO_TEST_CASE(function_calls)
 	compareVersions("f(uint256)", 36);
 }
 
+BOOST_AUTO_TEST_CASE(storage_write_in_loops)
+{
+	char const* sourceCode = R"(
+		contract test {
+			uint d;
+			function f(uint a) returns (uint r) {
+				var x = d;
+				for (uint i = 1; i < a * a; i++) {
+					r = d;
+					d = i;
+				}
+
+			}
+		}
+	)";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256)", 0);
+	compareVersions("f(uint256)", 10);
+	compareVersions("f(uint256)", 36);
+}
+
+BOOST_AUTO_TEST_CASE(retain_information_in_branches)
+{
+	// This tests that the optimizer knows that we already have "z == sha3(y)" inside both branches.
+	char const* sourceCode = R"(
+		contract c {
+			bytes32 d;
+			uint a;
+			function f(uint x, bytes32 y) returns (uint r_a, bytes32 r_d) {
+				bytes32 z = sha3(y);
+				if (x > 8) {
+					z = sha3(y);
+					a = x;
+				} else {
+					z = sha3(y);
+					a = x;
+				}
+				r_a = a;
+				r_d = d;
+			}
+		}
+	)";
+	compileBothVersions(sourceCode);
+	compareVersions("f(uint256,bytes32)", 0, "abc");
+	compareVersions("f(uint256,bytes32)", 8, "def");
+	compareVersions("f(uint256,bytes32)", 10, "ghi");
+
+	m_optimize = true;
+	bytes optimizedBytecode = compileAndRun(sourceCode, 0, "c");
+	size_t numSHA3s = 0;
+	eth::eachInstruction(optimizedBytecode, [&](Instruction _instr, u256 const&) {
+		if (_instr == eth::Instruction::SHA3)
+			numSHA3s++;
+	});
+	BOOST_CHECK_EQUAL(1, numSHA3s);
+}
+
+BOOST_AUTO_TEST_CASE(store_tags_as_unions)
+{
+	// This calls the same function from two sources and both calls have a certain sha3 on
+	// the stack at the same position.
+	// Without storing tags as unions, the return from the shared function would not know where to
+	// jump and thus all jumpdests are forced to clear their state and we do not know about the
+	// sha3 anymore.
+	// Note that, for now, this only works if the functions have the same number of return
+	// parameters since otherwise, the return jump addresses are at different stack positions
+	// which triggers the "unknown jump target" situation.
+	char const* sourceCode = R"(
+		contract test {
+			bytes32 data;
+			function f(uint x, bytes32 y) external returns (uint r_a, bytes32 r_d) {
+				r_d = sha3(y);
+				shared(y);
+				r_d = sha3(y);
+				r_a = 5;
+			}
+			function g(uint x, bytes32 y) external returns (uint r_a, bytes32 r_d) {
+				r_d = sha3(y);
+				shared(y);
+				r_d = bytes32(uint(sha3(y)) + 2);
+				r_a = 7;
+			}
+			function shared(bytes32 y) internal {
+				data = sha3(y);
+			}
+		}
+	)";
+	compileBothVersions(sourceCode);
+	compareVersions("f()", 7, "abc");
+
+	m_optimize = true;
+	bytes optimizedBytecode = compileAndRun(sourceCode, 0, "test");
+	size_t numSHA3s = 0;
+	eth::eachInstruction(optimizedBytecode, [&](Instruction _instr, u256 const&) {
+		if (_instr == eth::Instruction::SHA3)
+			numSHA3s++;
+	});
+	BOOST_CHECK_EQUAL(2, numSHA3s);
+}
+
 BOOST_AUTO_TEST_CASE(cse_intermediate_swap)
 {
 	eth::KnownState state;
@@ -868,6 +975,35 @@ BOOST_AUTO_TEST_CASE(control_flow_graph_do_not_remove_returned_to)
 	checkCFG(input, {u256(2)});
 }
 
+BOOST_AUTO_TEST_CASE(block_deduplicator)
+{
+	AssemblyItems input{
+		AssemblyItem(PushTag, 2),
+		AssemblyItem(PushTag, 1),
+		AssemblyItem(PushTag, 3),
+		u256(6),
+		eth::Instruction::SWAP3,
+		eth::Instruction::JUMP,
+		AssemblyItem(Tag, 1),
+		u256(6),
+		eth::Instruction::SWAP3,
+		eth::Instruction::JUMP,
+		AssemblyItem(Tag, 2),
+		u256(6),
+		eth::Instruction::SWAP3,
+		eth::Instruction::JUMP,
+		AssemblyItem(Tag, 3)
+	};
+	BlockDeduplicator dedup(input);
+	dedup.deduplicate();
+
+	set<u256> pushTags;
+	for (AssemblyItem const& item: input)
+		if (item.type() == PushTag)
+			pushTags.insert(item.data());
+	BOOST_CHECK_EQUAL(pushTags.size(), 2);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }